The invention concerns contraception and the prevention of sexually-transmitted diseases by means of a barrier-type device and further concerns a barrier-type device which engages the cervix by extending into the fornices and seals circumferentially against the vagina in the vicinity of the cervix.
The prior art devices for intravaginal, barrier-type prevention of conception and sexually transmitted disease include the diphragm and the cervical cap. The diaphragm, when seated intravaginally, acts as a barrier to prevent sperm from entering the os of the cervix. A spermicide is used on the inside of the diaphragm to kill sperm traversing over the edge of the diaphragm. Characteristically, the diaphragm is a shallow rubber cup with a rim. A round, coiled metal spring is disposed in the rim. The diaphragm is inteded for intravaginal disposition between the posterior aspect of the public bone and the posterior fornix. When thus seated, the diaphragm presses against the vaginal wall to form a continuous barrier therewith.
The cervical cap is a small, vaulted or domed device, more rigid than the diaphragm, and dimensioned to fit over a cervix, where it is retained by suction, rather than spring tension as is the diaphragm. The cap includes a dome which rises from a rim. The cap is slipped over the cervical protrusion to block access to the uterus through the cervical os.
None of these barrier-type devices is adapted to fit in close anatomical sealing engagement between the vagina and the cervix. The diaphragm is held against the upper part of the vaginal canal by the tension of the spring in its rim, while the cervical cap typically engages only the tip of the cervix. Both of these devices can be dislodged by sexual arousal, coital activity, or orgasm. As is known, such dislodgment can reduce the effectiveness of the barrier and permit unintended fertilization or unwanted infection, or worse, both.
In failing to take into account the anatomy and physiology of the vagina and the cervix, the prior art barrier-type devices form imperfect barriers against the penetration of sperm and agents of sexually transmitted diseases into the uterus. As is known, fertilization and infection take place within the uterus, therefore the more sound the barrier to the cervical os, the greater the likelihood of preventing such fertilization or infection. With the emergence of the AIDS (acquired immune deficiency syndrome) epidemic, the risk of life-threatening infection accompanying heterosexual activity is increasing steadily. Therefore, there is a compelling need for intravaginal, barrier-type devices which can substantially decrease the risk of infection by significantly increasing the effectiveness and reliability of the barrier to entry of bodily fluids such as semen, into the cervix.
Accordingly, it is an urgent objective of the invention to provide an intravaginal, barrier-type device which accounts for, and takes advantage of, the anatomy and physiology of the vagina in the vicinity of the cervix to form a more perfect, and a more reliable, seal against the movement of sperm and micro organisms from the vaginal canal through the cervical os into the uterus.
A significant advantage of such a device is the simultaneous reduction of the prospects of conception.